Will it work? Ralink RT2770 RT2750 chipset on BT5R2. What "idea" WiFi adapter?

Hi community,

I run BT5R2 Gnome 64 bits on a LG R510 laptop to get familiar with basic wifi cracking skills. I remember seeing a picture of an undocumented 10-wifi cards portable computer based upon a micro-ITX motherboard placed in a Pelican case. From this setup, I kept the idea of putting more than one card on the laptop, at least to monitor more than one network at once. Interestingly, the R510 doesn't have ne mini PCI-Express slot, but TWO (though it doesn't have spare antennas).

The good news is the internal card is recognized, and I also added a ZyDAS 1211-based USB interface that doesn't measure transmission power. But for some reason, it seems that the reaver attacks I'm trying to perform don't succeed (mostly timeouts).

From what I could find, this could mean the access point is too far, or the card doesn't properly perform raw injection. As such, I began looking for the "ideal" WiFi adapter that would support b, g and n, and perhaps a in monitor mode, be powerful enough to perform attacks dependant upon transmission power, and, of course, that would be supported out-of-the-box by major Linux distros, including BT5R2. Mac OS X compatibility would also be a big plus since it would allow for use with VirtualBox.

Then I came across this AWUS051NH, but a googling of the chipset + bt5 yielded varying experience from different peoples. There are many other variations of ALFA adapters, and I'm at a loss trying to find out the best one.

Does the 051 have two chipsets indeed?
Where can it be found at a reasonable price?
How does it perform in BT5 R2, really?